gotest: avoid conflicts with the name of the tested package
gotest: avoid conflicts with the name of the tested package

Uses a generic solution of renaming the tested package, instead of
using cryptic names for all other imports, variables and methods
in the generated _testmain.go file.

Fixes issue 2346.

R=golang-dev, r, adg
CC=golang-dev, rsc
http://codereview.appspot.com/5254061

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

sanjosh/sanjos100-tipc,webfd/go-zh,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,bryanxu/go-zh,scirelli/scirelli-go,d0f/go-zh,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,mhennings/marcohennings-go,webfd/go-zh,bryanxu/go-zh,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,scirelli/scirelli-go,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1,webfd/go-zh,Triskite/willstone-goclone,scirelli/scirelli-go,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,scirelli/scirelli-go,rdp/rogerpack2005-golang,bryanxu/go-zh,mhennings/marcohennings-go,d0f/go-zh,bryanxu/go-zh,Triskite/willstone-goclone,webfd/go-zh,d0f/go-zh,bryanxu/go-zh,rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,mhennings/marcohennings-go,rdp/rogerpack2005-golang,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,d0f/go-zh,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,Triskite/willstone-goclone,d0f/go-zh,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,webfd/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,scirelli/scirelli-go,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,Triskite/willstone-goclone,Triskite/willstone-goclone,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,d0f/go-zh,rflanagan/reginaldflanagan-project1